Welcome to the Glass Age

51 teeth, a new fluoride-containing bioactive glass composition, BioMin ® F (BioMin Technologies, UK), is now on the market. It releases fluoride ions in addition to calcium and phosphate when in contact with saliva, resulting in a tooth mineral that is less likely to dissolve in acids, for example when we consume lemonade or fruit juices. Bioglass is also used in several cosmetic creams, particularly as Vitryxx ® (Schott AG), a very finely ground particulate. Vitryxx is thought to have anti-ageing benefits, such as reducing redness and wrinkles. Glass-based materials in dentistry When glass is heated above a certain temperature, it crystallises, forming a glass-ceramic. Glass-ceramics can show interesting combinations of properties, such as transparency and high strength. We know them for example from cooker tops, where they can survive drastic changes in temperature without shattering. In the field of dentistry, glass-ceramics are used with great success to replace teeth [12], as they are strong enough to withstand the forces during chewing and can be made to look just like natural teeth. They are also chemically durable and survive constant exposure to saliva, low pH during the drinking of juices or changing temperatures when we eat ice cream or drink hot beverages. Glass-ceramics are used to make dental inlays, crowns and bridges, and often consist of a combination of different glass-ceramics. For example, lithium disilicate is strong enough to be used as the main framework in bridges, while leucite or fluorapatite glass-ceramics give the appearance of natural tooth (Figure 3.8). But even in dentistry soluble glasses are used. A certain type of glass that contains aluminium ions, referred to as Figure 3.8. Application of a dental inlay made from a leucite glass-ceramic: (a) initial amalgam filling, (b) preparation of the molar for inlay restoration, (c) final state after adhesive luting and polishing of the inlay. Source: Ritzberger et al. [13] (CC BY 3.0).